Spectra of visual pigments and characteristics of visual pigment bleaching stages will be studied in order to gain information about the nature of the visual pigments as well as the nature of the visual transduction process. This will be done by studying both visual pigments themselves and compounds which model the visual pigment chromophore. Studies will employ standard spectroscopic methods as well as two-photon spectroscopy and microsecond, nanosecond, and picosecond flash kinetic spectroscopy.